Adding a qt. of 5w40 Mobil 1 to 5w30

[pbm]

I picked up a few quarts of M1 Turbo Diesel Truck 5w40 at the AZ clearance last year.
I really have no use for them but I was thinking of substituting a quart of this for a qt. of regular 5w30 Mobil 1 in my Cruze's turbo now that it's out of warranty.
(The plan would be to use 3.25 qts. regular M1 5w30 and 1 qt 5w40 in the warmer weather)
The 1.4T calls for a 40 wt. in Europe so thickening the 5w30 slightly shouldn't be a problem.
Does anybody see a problem with doing this?

 

[il_signore97]

No issue with doing that to use up your extra qts of 5W40. You will likely not notice the difference at all.

 

[pbm]

I know the TDT uses Magnesium so adding a quart would add some magnesium and probably take away some moly.
I'm not sure if this would require a shortened OCI but I only do about 6 to 6.5K anyway. My 2011 Cruze has the overly optimistic OLM which was corrected in either 2012 or 2013 (although GM has never admitted to it). I have never gone below 30% because I thought it was optimistic even before they 'adjusted' it.

 

[147_Grain]

You can add the 5W-40 in warmer climates and run your normal OCI with no issues.

 

[pbm]

Originally Posted By: 147_Grain
You can add the 5W-40 in warmer climates and run your normal OCI with no issues.



Great.....thanks.

 

[CATERHAM]

I'd pick up some (Mobil made) TGMO 0W-20 and cut the diesel 5W-40 with it. This will still give you a heavier than spec' 5W-30 but will a higher VI and keep the ZDDP level closer to spec'.

 

[CATERHAM]

Sorry meant to include "cut the 5W-40 50% with it".

 

[Sonic]

Originally Posted By: pbm
I picked up a few quarts of M1 Turbo Diesel Truck 5w40 at the AZ clearance last year.
I really have no use for them but I was thinking of substituting a quart of this for a qt. of regular 5w30 Mobil 1 in my Cruze's turbo now that it's out of warranty.
(The plan would be to use 3.25 qts. regular M1 5w30 and 1 qt 5w40 in the warmer weather)
The 1.4T calls for a 40 wt. in Europe so thickening the 5w30 slightly shouldn't be a problem.
Does anybody see a problem with doing this?




Funny, I just did this EXACT thing this morning with the oil change on my Subaru. I used 1.5qts of the Mobil TDT 5w40 and 2.7qts of Mobil 5w30. I've had a gallon of the TDT sitting in my stash for over a year. My mix gave me a thick 30 grade for the summer. Gotta use it up somehow, I may use the rest in a mix for my motorcycle this fall (with some M1 15w50 or 20w50).

 

[pbm]

Originally Posted By: CATERHAM
I'd pick up some (Mobil made) TGMO 0W-20 and cut the diesel 5W-40 with it. This will still give you a heavier than spec' 5W-30 but will a higher VI and keep the ZDDP level closer to spec'.


Caterham:
Do you think that mix would do well with the turbo?
What about 50/50 with AFE 0w20?

 

[CATERHAM]

Yes I do (warranty explanations notwithstanding).
And AFE 0W-20 would work also but I'd increase the ratio of AFE to 60%.